Adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations and breast cancer risk in the Cancer de Màma (CAMA) study

Abstract

Objective We investigated the association between adherence to the recommendations of the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and breast cancer (BC) risk in the Cancer de Màma (CAMA) study in a Mexican population. Design Population-based case-control study. Subjects Incident BC cases (n 1000) and controls (n 1074) matched on age, region and health-care system were recruited. Setting In-person interviews were conducted to assess BC risk factors and habitual diet was assessed with an FFQ. Conformity to the WCRF/AICR recommendations was evaluated through a score incorporating seven WCRF/AICR components (body fatness, physical activity, foods and drinks that promote weight gain, plant foods, animal foods, alcoholic drinks and breast-feeding), with high scores indicating adherence to the WCRF/AICR recommendations. Results No statistically significant associations between WCRF/AICR score and risk of BC were observed. After excluding BMI from the WCRF/AICR score, the top quartile was associated with a decreased BC risk overall, with ORQ4-Q1=0·68 (95 % CI 0·49, 0·92, P trend=0·03), and among postmenopausal women, with ORQ4-Q1=0·60 (95 % CI 0·39, 0·94, P trend=0·03). Inverse associations were observed between BMI and risk of BC overall and among premenopausal women, with OR=0·57 (95 % CI 0·42, 0·76, P trend<0·01) and 0·48 (95 % CI 0·31, 0·73, P trend<0·01), respectively. Physical activity level was inversely associated with BC risk. Conclusions The WCRF/AICR index was not related with BC risk in the CAMA study. A combination of six components excluding BMI showed strong protective associations, particularly in postmenopausal women. Further prospective studies are required to clarify the role of adherence to WCRF/AICR recommendations, particularly with respect to BMI, in the Mexican population.